Rinse-off conditions are known generally in the art. U.S. Pat. Nos. 5,578,299 and 5,888,492 both to Starch, for example describe rinse off conditioning compositions. Both references disclose the possible use of fatty acids as emollient, but fail to disclose use of unsaturated fatty acids or recognize the unexpected benefits unsaturated acids could bring. Emollients/oils also may comprise up to 40% of the compositions compared to generally lower oil compositions of the invention. In addition, both references require use of at least 1% nonionic surfactants. In preferred embodiments of the subject invention, the compositions comprise less than 1% by wt., preferably 0.5% or less, more preferably 0.15% or less surfactant and may preferably be absent altogether.
U.S. Pat. No. 5,928,632 to Reusch discloses rinse off skin conditioners which are surfactant free. There is no discussion of fatty acid and the only reference to fatty acid seems to be use of 0.5% stearic (saturated fatty acid) in a comparative formulation in Table 1.
U.S. Pat. No. 6,699,488 to Deckner discloses skin conditioning compositions comprising high internal phase (HIP) emulsion comprising oil, stabilizers and water. To the extent the compositions may contain fatty acids (column 9, lines 33-38), the reference teaches away from unsaturates and discloses the fatty acids are saturated (straight or branched chain).
U.S. Publication 2004/0223992 discloses wet skin compositions comprising gel networks which in turn comprise nonionic hydrophilic surfactant and hydrophobic structuring agent (¶0040). The structuring agent may be saturated hydroxy fatty acid.
U.S. Pat. Nos. 6,645,511 or 6,716,440, both to Aronson et al. disclose wet skin compositions with non-greasy feel. The only mention of fatty acids seem to be as sensory modifiers (column 9, line 24 of '440), but there is no disclosure of use of unsaturated fatty acids or of ratio of unsaturates to saturates.
U.S. Pat. No. 6,903,057 to Tsaur discloses compositions comprising non-gelatinized starch structuring system which compositions may comprise fatty acid (e.g., skin benefit agent). The compositions must comprise surfactant and, in addition, there is no disclosure of unsaturated fatty acid or ratio of unsaturated to saturated. Applicants have filed a related application, (U.S. Publication No. 2007/0032393 A1) which is a wet skin composition having little or no surfactant. The reference discloses use of unsaturated fatty acid, but in a system where all examples have at least 4% structurant (i.e., non-pregelatinized starch structurant). Compositions of the invention comprise 3% or less structurant and no non-pregelatinized starch structurant. Compositions of the reference also must comprise 15% and up oil).
In applicants co-pending application Ser. No. 11/748,943. filed May 15, 2007, applicants disclose a relatively low oil shower gel with lower amounts of structurants. In this reference, although use of fatty acid is broadly disclosed, there is no recognition of criticality of unsaturated fatty acid (ratio of unsaturated to saturated of preferably at lest 1:1, more preferably 2:1) in a relatively low surfactant, low structurant system.